It is known to provide so-called Location Based Services (LBS) in cellular communication networks, such as a cellular wireless telephone network. Such services typically comprise a mechanism for estimating the location of a mobile terminal, e.g. with the help of a Global Positioning System (GPS, Galileo, Glonass) or a Mobile Positioning System (MPS) that may use Cell-ID information or algorithms based on timing advances and on triangulation for determining the position of a mobile terminal. Said LBS mechanisms are known to enable content delivery based on the location of the user (mobile terminal). Based on the knowledge of the mobile terminal's location, specific location based services can be offered to said mobile terminal, e.g. alert messages for upcoming road traffic hazards or indications toward deviations to avoid traffic jams. It is furthermore known to broadcast information with the help of so-called Cell Broadcast Services (CBS), in order to distribute information to mobile terminals within one or more cells. The respective mobile terminals have to enable the listening of the respective broadcast channel. So-called Multimedia Broadcast and Multicast Service (MBMS) are known that provides a broadband broadcast to mobile terminals.
Such data communication in cellular communication networks is dominated by using a request response communication mechanism that is triggered by the mobile terminal, or point-to-point (P2P) data communication using Short Message Service (SMS) and Multimedia Message Service (MMS). Further, said LBS technologies or the aforementioned broadcast technologies are being introduced for enabling an enriched request response communication.
However, the conventional methods and concepts for providing location based (geographical) unicast network services in cellular communication networks may suffer from various drawbacks. Said unicast network services employ mechanisms for information delivery to the mobile terminals by establishing a dedicated connection to the mobile terminals and/or sending messages (SMS/MMS) specifically addressed to said mobile terminals. In particular, such concepts may rely on keeping a client database with all clients' locations (i.e. the locations of the mobile terminals) and on updating this information on a regular basis. The regular update may be effected by requesting status data from the mobile terminals, e.g. location updates. In the case of vehicle mounted mobile terminals this may be necessary frequently, since the travelling speed of the vehicles results in a substantial change of the location within even relatively short periods of time (e.g. a vehicle moving at 180 km/h moves around 1,500 m within 30 seconds). This may—in turn—result in an occupation of substantial network communication and processing resources by such a geographical network service, since every service using the location-based addressing would load the cellular communication network with additional data traffic for continuous client localization.
In addition to the above, the actual locations of the mobile terminals, or at least information indicating the respective locations, have to be kept in some database in order to allow for any location-based network service. Further, in order to be able to send specific messages to these location-based selected mobile terminals, there will be also an association of the location data to identification data of the respective mobile terminals, for example their respective telephone numbers for sending and addressing messages thereto. This implies that the respective information represents sensitive data which a Mobile Network Operator (MNO) of a specific cellular communication network may not be allowed to reveal freely to third parties. Contractual arrangements between the MNO and the users who are the subscribers to the services of the cellular communication network and own—or at least operate—the mobile terminals, and/or national legislation may require that any association of an actual location of a mobile terminal (i.e. also a user) to identification information is to be dealt with confidentiality, and must thus be kept inside the MNO's network so that third parties cannot gain access to this information. The MNO <1>s network may not only comprise the cellular communication network that the MNO operates or rents from some other provider for offering cellular communication network based services, but also the respective internal networks, such as the respective intranets and correspondingly secured interfaces to the internet. Revealing the location information in combination with identification information may require the consent of every individual mobile terminal user. As a consequence, any location-based addressing may only be available to specific services and not to other services and/or other service providers. As far as the regular location update is concerned, the disadvantage of such regular probe data can be manifold. On one hand, there is generated a heavy network load when the client database is queried to determine other clients in the proximity of an event, say a road accident. This load will increase quadratic with the total number of served clients and mobile terminals and dimensioning the service for a larger area with the correct capacity may become challenging. On the other hand, regular and unmanaged upload of probe data may block valuable radio resources for other users and services. However, such higher network load in a cellular communication network may also have a negative impact on the delay performance.
Still further, the accuracy of the position information differs for different technologies. The above-mentioned network-based positioning MPS provides only an accuracy of several hundred meters depending on the cell diameter.
Although satellite-based localisation mechanisms are more precise down to several meters, this can still be not accurate enough since vehicle mounted mobile terminals may—as already mentioned above—travel fast. In order to keep a geographical network service in such situations reliable, it would be required to provide the system with location updates several times per minute.
It is thus an object of the present invention to provide a network service of a cellular communication network for providing information based on the location of the mobile terminals, while avoiding congestion of uplink radio resources and without the need of revealing the client's location information in association with the respective identification information.